Several stages of recovery can be observed when monoamine neurotoxins (6-OHDA or 5,6 DHT) are injected intraventricularly into rats housed in a large, complex environment. A peak of social disruptions occurs 25 days after lesioning; at this time the 6-OHDA animals are most dominated and the 5,6 DHT rats most dominant. Recovery from neurotoxins in distinctively different in isolate and in rat colony housed rats. Colony-housed rats become more similar to their controls the longer after lesioning they are left in the colony, whereas isolates show large fluctuations in stages of recovery. Rats administered 6-OHDA and allowed to recover in isolation develop a supersensitivity to d-amphetamine which does not develop in animals allowed to recover in a social environment. But while social-housed rats recover better behaviorally, isolate-housed rats recover better biochemically, as measured by uptake of labeled Norepinephrine in the brainstem and frontal cortex and histofluoresence smears. Social behaviors of rats with electrolytic lesions of the Locus Coeruleus are distinctively different from rats with lesions of Substantia Nigra pars compacta. LC rats behave like rats with ventricular 6-OHDA (underaroused and socially dominated) whereas SN rats are hyperactive and hyperaggressive. D-amphetamine and Methylphenidate potentiate the rearing response of rats (an observing response) in different ways. D-amphetamine induces frequent, brief responses (as does anticholinergics) whereas methylphenidate induces prolonged responses (as does cholinergic agonists).